【発明の詳細な説明】[Detailed description of the invention]
本発明は、二酸化炭素により種実から油脂を短
時間で効率的に抽出分離する方法に関する。
液状または超臨界状の二酸化炭素は、優れた溶
質抽出能力を有し、従来よりこの特性を利用して
種実中の油脂を抽出分離することなどが行われて
いる。
一般に、種実中の油脂（溶質）を溶剤で溶解し
たうえ（溶液）抽出分離する場合、大別して、次
の５段階が考えられる。すなわち、(1)溶剤の固体
表面への移動、(2)溶剤の固体内部への拡散、(3)溶
質の溶解、(4)溶液の固体内部からの拡散、(5)溶液
の固体表面からの移動に分けられる。そして、こ
の５段階のうち、第４番目の溶液の固体内部から
の拡散がこの抽出系の律速段階であると考えられ
ている。
したがつて、従来の液状または超臨界状の二酸
化炭素中に種実等を静置する抽出分離方法では、
抽出時間が長くかかり、かつ十分な抽出効率が得
られないという欠点があつた。
本発明は上記事情に鑑みてなされたもので、種
実中の油脂を短時間で効率よく抽出できる抽出分
離方法を提供することを目的とし、抽出操作中二
酸化炭素の圧力を急速減圧し、さらに再昇圧する
圧力変動操作を１回以上行い、その際、急速減圧
後の圧力を、二酸化炭素が気体状態とならない圧
力にして、種実内部からの溶液の拡散を促進する
ようにしたことを特徴とするものである。
以下、図面を参照して本発明を詳しく説明す
る。
図面は、本発明の抽出分離方法の実施に好適な
抽出分離装置の一例を示すものである。
原料貯槽１から米殻、胡麻種子、綿実などの種
実が弁２を経て所定量オートクレーブ３に送られ
る。ついで、弁２が閉じられ、弁４，５，６が開
けられ、液状二酸化炭素が二酸化炭素貯槽７から
所定量オートクレーブ３に送り込まれる。その
後、液ポンプ８を運転し、二酸化炭素を圧送して
オートクレーブ３内を80〜300バールの範囲内の
所定圧力に昇圧し、同時にオートクレーブ３を囲
むヒータ９を動作せしめてオートクレーブ３内を
０〜100℃の範囲内の所定温度にまで昇温させる。
オートクレーブ３内の溶剤である二酸化炭素が所
定の圧力、温度に達したならば、その状態を一定
時間、例えば１〜100分間程度保持し、抽出を行
う。
上記二酸化炭素の抽出条件は、二酸化炭素の抽
出能力およびオートクレーブ３配管などの装置の
設計圧力などによつて決められるもので、高温、
高圧となれば二酸化炭素の溶剤としての溶解抽出
能力は向上して好ましいが、300バールを越える
圧力では実用的観点から経済的でない。また温度
が100℃を越えると種実中の蛋白質、澱粉等が変
質を起し好ましくない。80バール未満、０℃未満
であれば、溶解抽出能力が十分でなく、抽出時間
が長くなり経済的でない。また、保持時間は、油
脂の抽出率、種実の種類、二酸化炭素と種実の量
比、二酸化炭素の温度、圧力等によつて適宜決め
られる。
次に、所定時間上記状態に保持したならば、減
圧弁１０を大きく開き、オートクレーブ３内の圧
力を所定の圧力まで急速減圧する。減圧後の圧力
は、次工程の再昇圧の操作上から、その温度で二
酸化炭素が気体状態とならない圧力以上とする。
すなわち、二酸化炭素の温度が31℃以上では73.8
バール以上、20℃では60バール以上、０℃では35
バール以上である。また、この減圧後の圧力と先
の保持圧力との差が大きい程、溶液の種実表面へ
の拡散が良好となつて好ましい。
圧力が所定の圧力まで低下したならば、ただち
に減圧弁１０を閉じオートクレーブ３内の圧力を
元の圧力にまで再昇圧し、再び高圧側で抽出を行
なう。
そして、この圧力変動操作を必要に応じて１回
以上数回繰り返えす。この操作中、抽出液は減圧
弁１０を通過して減圧され分離槽１１に入り、こ
こでガス状二酸化炭素と抽出油脂とに分離され
る。ガス状二酸化炭素は分離槽１１からロータメ
ータ１２および積算流量計１３を経て系外に放出
される。また、抽出された油脂は、分離槽１１の
底部から弁１４を経て取り出され、製品とされ
る。
なお、上記抽出操作に際して、必要に応じ抽出
助剤としてアルコール類、酸類、ハイドロカーボ
ン類を弁１５からオートクレーブ３中に導入して
もよい。また、図中符号１６は減圧弁１０の開閉
動作を制御する圧力調節器、１７はこの圧力調節
器１６の動作をシーケンス制御するシーケンサ、
１８は冷却器である。
このような抽出分離法によれば、抽出操作時、
二酸化炭素の圧力を急速減圧し、さらに再昇圧す
る圧力変動操作を１回以上行い、その際、急速減
圧後の圧力を、その温度での二酸化炭素が気体状
態とならない圧力以上とするので、種実中に浸透
し、種実内の油脂を溶解して油脂溶液となつた二
酸化炭素が、上記急速減圧によつて種実内から種
実表面に急速に拡散してゆくことになり、先の律
速段階の拡散速度が大きくなる。よつて、抽出系
全体の油脂の抽出速度が大きくなり、抽出時間の
短縮、抽出効率の向上が計れるとともに、次の再
昇圧の際の液ポンプ８の運転動力が少なくて済
み、経済的である。さらに、抽出された油脂は圧
力及び温度操作により、二酸化炭素と容易に分離
することができ、蒸留操作などの分離操作を行う
必要もなく、分離槽１１の底部より取り出され、
そのまま製品とすることもできる。また、抽出残
査の種実は砕け等の発生がなく、そのままの形状
でオートクレーブ３より回収できる。
以下、実施例を示して本発明を具体的に説明す
る。
図面に示した抽出分離装置を用い、種実に精米
度91％の白米（昭和57年産ササニシキ）を用い、
これより油脂を抽出した。
〔実施例 １〕
上記白米試料130ｇをオートクレーブ３に入れ、
二酸化炭素貯槽７から液状二酸化炭素を液ポンプ
８を運転してオートクレーブ３中に送り込み、ヒ
ータ９を動作させて、オートクレーブ３内を圧力
250バール、温度35℃に保持し、５分間この状態
に保ち抽出した。ついで減圧弁１０を開きオート
クレーブ３内を100バールになるまで減圧させる。
そして、ただちに減圧弁１０を閉じ、元の圧力
250バールにまで再昇圧してさらに５分間この状
態を保持し抽出した。この圧力を保持しながら減
圧弁１０を開き、減圧時に放出した二酸化炭素を
含めて、合計250Nl放出した。つぎに、オートク
レーブ３内圧力を大気圧まで落し、試料を取り出
す。この場合は減圧操作は１回である。
〔実施例 ２〕
また、同様の条件で減圧操作２回の実験を行つ
た。試料を取り出したのち、試料中の粗脂肪含量
を「国税庁所定分析法注解」に拠つて定量した。
〔比較例〕
比較のために、従来法によつて抽出分離を行つ
た。同一試料130gをオートクレーブ３内に入れ、
二酸化炭素を供給し、圧力250バール、温度35℃
で30分間静置した。その後、液ポンプ８を運転し
て圧力を保持しながら減圧弁１０を開き、15分間
250Nlの二酸化炭素で抽出した。ついで、オート
クレーブ３内を大気圧まで落し、試料を取り出
し、同様にして粗脂肪量を定量した。
上記抽出操作による粗脂肪量の変化を次表に示
す。
The present invention relates to a method for efficiently extracting and separating fats and oils from seeds using carbon dioxide in a short time. Liquid or supercritical carbon dioxide has an excellent ability to extract solutes, and this property has been used to extract and separate fats and oils from seeds. In general, when oils and fats (solutes) in seeds are dissolved in a solvent and then extracted and separated (solution), the following five steps can be considered. Namely, (1) movement of the solvent to the solid surface, (2) diffusion of the solvent into the solid, (3) dissolution of the solute, (4) diffusion of the solution from the inside of the solid, and (5) diffusion of the solution from the solid surface. It can be divided into 1 movement. Of these five steps, the fourth step, diffusion of the solution from inside the solid, is considered to be the rate-determining step of this extraction system. Therefore, in the conventional extraction separation method of leaving seeds etc. in liquid or supercritical carbon dioxide,
The drawbacks were that the extraction time was long and sufficient extraction efficiency could not be obtained. The present invention was made in view of the above circumstances, and aims to provide an extraction separation method that can efficiently extract fats and oils from seeds in a short time. The method is characterized in that the pressure fluctuation operation of increasing the pressure is carried out one or more times, and at that time, the pressure after rapid depressurization is set to a pressure that does not turn carbon dioxide into a gaseous state, thereby promoting diffusion of the solution from inside the seeds. It is something. Hereinafter, the present invention will be explained in detail with reference to the drawings. The drawings show an example of an extraction and separation apparatus suitable for carrying out the extraction and separation method of the present invention. A predetermined amount of seeds such as rice husks, sesame seeds, and cotton seeds are sent from a raw material storage tank 1 to an autoclave 3 via a valve 2. Then, valve 2 is closed, valves 4, 5, and 6 are opened, and a predetermined amount of liquid carbon dioxide is fed into autoclave 3 from carbon dioxide storage tank 7. Thereafter, the liquid pump 8 is operated to pump carbon dioxide to raise the pressure inside the autoclave 3 to a predetermined pressure within the range of 80 to 300 bar, and at the same time, the heater 9 surrounding the autoclave 3 is operated to maintain a pressure inside the autoclave 3 of 0 to 300 bar. Raise the temperature to a specified temperature within the range of 100℃.
Once the carbon dioxide, which is a solvent in the autoclave 3, reaches a predetermined pressure and temperature, this state is maintained for a certain period of time, for example, about 1 to 100 minutes, and extraction is performed. The above carbon dioxide extraction conditions are determined by the carbon dioxide extraction capacity and the design pressure of the equipment such as the 3 autoclave piping.
A high pressure is preferable because it improves the ability to dissolve and extract carbon dioxide as a solvent, but a pressure exceeding 300 bar is not economical from a practical point of view. Furthermore, if the temperature exceeds 100°C, the protein, starch, etc. in the seeds will deteriorate, which is undesirable. If it is less than 80 bar and less than 0°C, the dissolution extraction ability will not be sufficient and the extraction time will be long, making it uneconomical. Further, the holding time is appropriately determined depending on the extraction rate of fats and oils, the type of seeds, the quantitative ratio of carbon dioxide to seeds, the temperature and pressure of carbon dioxide, and the like. Next, after maintaining the above state for a predetermined period of time, the pressure reducing valve 10 is opened wide to rapidly reduce the pressure inside the autoclave 3 to a predetermined pressure. The pressure after depressurization is set to be at least a pressure at which carbon dioxide does not turn into a gaseous state at that temperature, in view of the operation of re-pressurizing in the next step.
In other words, when the temperature of carbon dioxide is 31℃ or higher, it is 73.8
Over bar, over 60 bar at 20℃, 35 at 0℃
More than a crowbar. Further, the larger the difference between the pressure after this pressure reduction and the previous holding pressure, the better the diffusion of the solution to the seed surface, which is preferable. When the pressure has decreased to a predetermined pressure, the pressure reducing valve 10 is immediately closed, the pressure inside the autoclave 3 is raised again to the original pressure, and extraction is performed again on the high pressure side. This pressure fluctuation operation can be repeated one or more times as necessary. During this operation, the extract passes through the pressure reducing valve 10, is depressurized and enters the separation tank 11, where it is separated into gaseous carbon dioxide and extracted oil and fat. Gaseous carbon dioxide is discharged from the separation tank 11 to the outside of the system via a rotameter 12 and an integrated flowmeter 13. Further, the extracted fats and oils are taken out from the bottom of the separation tank 11 via the valve 14 and made into a product. Note that during the above extraction operation, alcohols, acids, and hydrocarbons may be introduced into the autoclave 3 from the valve 15 as extraction aids, if necessary. Further, in the figure, reference numeral 16 is a pressure regulator that controls the opening/closing operation of the pressure reducing valve 10, and 17 is a sequencer that sequentially controls the operation of this pressure regulator 16.
18 is a cooler. According to such extraction separation method, during extraction operation,
A pressure fluctuation operation in which the pressure of carbon dioxide is rapidly reduced and then increased again is performed one or more times, and at that time, the pressure after rapid pressure reduction is set to a pressure higher than that at which carbon dioxide does not turn into a gaseous state at that temperature, so the seedlings are The carbon dioxide that penetrates into the seed and dissolves the oil and fat in the seed and becomes an oil and fat solution will rapidly diffuse from the inside of the seed to the surface of the seed due to the rapid depressurization described above, and the diffusion of the previous rate-limiting step will be completed. The speed increases. Therefore, the extraction rate of fats and oils in the entire extraction system increases, which shortens the extraction time and improves the extraction efficiency, and also reduces the operating power of the liquid pump 8 during the next re-pressurization, which is economical. . Furthermore, the extracted fats and oils can be easily separated from carbon dioxide by pressure and temperature manipulation, and there is no need to perform separation operations such as distillation, and the extracted fats and oils can be taken out from the bottom of the separation tank 11.
It can also be used as a product as is. In addition, the seeds of the extraction residue do not break apart and can be recovered from the autoclave 3 in their original shape. Hereinafter, the present invention will be specifically explained with reference to Examples. Using the extraction separation device shown in the drawing, using white rice (Sasanishiki produced in 1986) with a grain polishing rate of 91%,
Fats and oils were extracted from this. [Example 1] 130g of the above polished rice sample was placed in autoclave 3,
The liquid pump 8 is operated to feed liquid carbon dioxide from the carbon dioxide storage tank 7 into the autoclave 3, and the heater 9 is operated to increase the pressure inside the autoclave 3.
The temperature was maintained at 250 bar and 35° C. and kept in this state for 5 minutes for extraction. Then, the pressure reducing valve 10 is opened to reduce the pressure inside the autoclave 3 to 100 bar.
Then, immediately close the pressure reducing valve 10 and restore the original pressure.
The pressure was raised again to 250 bar and held for a further 5 minutes for extraction. While maintaining this pressure, the pressure reducing valve 10 was opened, and a total of 250 Nl was released, including carbon dioxide released during pressure reduction. Next, the pressure inside the autoclave 3 is lowered to atmospheric pressure and the sample is taken out. In this case, the pressure reduction operation is performed once. [Example 2] In addition, two experiments were conducted under the same conditions under reduced pressure. After the sample was taken out, the crude fat content in the sample was quantified based on "Comments on Analytical Methods Specified by the National Tax Agency." [Comparative Example] For comparison, extraction and separation was performed using a conventional method. Put 130g of the same sample into autoclave 3,
Supplying carbon dioxide, pressure 250 bar, temperature 35°C
It was left standing for 30 minutes. Then, operate the liquid pump 8 to maintain the pressure and open the pressure reducing valve 10 for 15 minutes.
Extracted with 250Nl of carbon dioxide. Then, the pressure inside the autoclave 3 was lowered to atmospheric pressure, the sample was taken out, and the amount of crude fat was determined in the same manner. The following table shows the change in crude fat amount due to the above extraction operation.
【表】
ここで抽出効率は、次式で表わす値を
C0−Ｃ／C0×100％
示す。
C0；処理前の粗脂肪含量
Ｃ：処理後の粗脂肪含量
表から明らかなように、実施例１の５分間抽出
減圧１回、５分間抽出のものは比較例の静置30分
間、抽出15分のものと同等の抽出効率を得られる
ことがわかり、この結果操作時間の短縮が可能で
あることがわかつた。また、実施例２の減圧２
回、合計抽出時間15分のものでは静置30分の比較
例に比べて抽出効率が17％向上していることがわ
かり、同時間の抽出では抽出効率が向上すること
が確認された。さらに、減圧回数を増せば、一層
の効率向上が期待できる。
以上説明したように、本発明の種実からの油脂
の抽出分離方法は、二酸化炭素を溶剤として抽出
する際、二酸化炭素の圧力を急速減圧し、さらに
再昇圧する圧力変動操作を１回以上行い、その
際、急速減圧後の圧力を、二酸化炭素が気体状態
とならない圧力にするものであるので、種実内部
からの溶液が強制的に拡散を促進されるため、抽
出時間の短縮化、抽出効率の向上が計られ、抽出
分離コストの低減化を達成することができる。[Table] Here, the extraction efficiency is expressed by the following formula: C 0 −C/C 0 ×100%. C 0 : Crude fat content before treatment C: Crude fat content after treatment As is clear from the table, the 5-minute extraction in Example 1 was extracted once under reduced pressure, and the 5-minute extraction was extracted after standing for 30 minutes in the comparative example. It was found that the same extraction efficiency as that of 15 minutes could be obtained, and as a result, it was found that the operation time could be shortened. In addition, the reduced pressure 2 of Example 2
It was found that the extraction efficiency was improved by 17% in the case where the total extraction time was 15 minutes compared to the comparative example which was left to stand for 30 minutes, and it was confirmed that the extraction efficiency was improved when the extraction time was the same. Furthermore, if the number of times of depressurization is increased, further efficiency improvement can be expected. As explained above, in the method for extracting and separating oils and fats from seeds of the present invention, when extracting carbon dioxide using carbon dioxide as a solvent, the pressure of carbon dioxide is rapidly reduced, and then the pressure is increased again, at least once. At that time, the pressure after rapid decompression is set to a pressure that does not turn carbon dioxide into a gaseous state, so the solution from inside the seeds is forced to diffuse, reducing extraction time and improving extraction efficiency. It is possible to achieve improvements in extraction and separation costs.
【図面の簡単な説明】[Brief explanation of drawings]
図面は本発明の抽出分離方法に用いられる抽出
分離装置の一例を示す概略構成図である。
１……原料貯槽、３……オートクレーブ、７…
…二酸化炭素貯槽、８……液ポンプ、９……ヒー
タ、１０……減圧弁、１１……分離槽。
The drawing is a schematic configuration diagram showing an example of an extraction and separation apparatus used in the extraction and separation method of the present invention. 1...Raw material storage tank, 3...Autoclave, 7...
...carbon dioxide storage tank, 8...liquid pump, 9...heater, 10...pressure reducing valve, 11...separation tank.